Mount for ring cores



May 9, 1961 c. H. Hx-:cKLE-R, JR 2,983,886

MOUNT FOR RING ooREs Filed Dec. 30, 1955 2 Sheets-Sheet 1 y mj] A 7 l @MQW if n L Eg' .4. in@

May 9, 1961 c. H. HECKLER, JR 2,983,886

MOUNT FOR RING comas Filed Dec. 50, 1955 2 Sheets-Sheet 2 AZTENEX States Patent 2,983,886 Patented May 9, 1961 fhce MoUNT non RING coREs Clarence H. Heckler, Jr., Pennsauken, NJ., assignor to Radio Corporation of America, a corporation of Delaware Filed Dec. 30, 1955, Ser. No. 556,635

Claims. (Cl. 336-92) This invention relates to means for mounting ring cores, and, more particularly, to methods of and means for providing a plug-in mount for wound magnetic coresA In View of the increasingly extensive use of printed wiring and automatic production methods, it is desirable to provide means for mounting wound magnetic ring cores in a manner which facilitates subsequent handling, either manually or automatically.

An object of this invention is .to provide a protective support for a wound magnetic ring core.

Another object of this invention is to provide a plug-in mounting for a wound magnetic ring core which facilitates the handling of the core.

A further object of this invention is to provide a method for forming a protective mount for a wound magnetic ring core. l

In accordance with the present invention a plurality oi conductors are supported in parallel relation and are bent intermediate their ends to form a supporting plane transverse to the parallel conductors. A wound ring core is secured to the supporting plane. The assembled core and conductors are placed in -a casting form and a layer of liquid plastic is provided which encases a portion of the parallel conductors. An open faced housing is placed over the core and into the liquid plastic. The plastic, upon setting, seals itself to` the housing walls to form a closing wall for the housing and supports the conductor and core with respect to the housing. The closing wall then forms the base for the structure.

A mount formed in accordance with the above process comprises a base, conductors partially encased in the base which form pins and the core supporting platform, and a housing which is closed by the plastic base.

The novel features of the invention, as well as additional `objects and advantages thereof, will be understood more fully from the following description when read in connection with the accompanying drawings, in which:

Figure l is a top view of a base member having four conductors extending through it and being bent to form a platform;

Figure 2 is a View in elevation, partially broken away, of the base member vof Figure l;

Figure 3 is a view of a wound ring core;

Figure 4 is a view in elevation of the ring core of Figure 3 secured tothe base member of Figure 2;

Figure 5 is atop view of the assembly of Figure 4;

Figure 6 is a sectional view in elevation of the assembly of Figure 4 placed in a casting form, and a housing for the assembly adjacent thereto;

Figure 7 is a sectional View in elevation of a complete lcore mounting assembly;

Figure 8 is a vieW in elevation, partially broken away, illustrating an alternative method of assembling the conductors and the core;

Figure 9 is a sectional View showing the alternative method and assembled parts of Figure 8 and also showing an alternative mounting structure; and

Figure l0 is a sectional view in elevation of the completed assembly of Figure 9.

Referring now in more detail to Figures 1 through 7 of the accompanying drawings, one method of assembling an illustrative embodiment of a core mount will be described. The foundation element for the mount struc-ture is a base member 11 which is in the form of a circular disc made of an insulating material, such as a plastic material for example. A plurality of vconductors 13 are rigidly fixed in the base member 11 and extend through the member and beyond both faces thereof. In the drawings, four of these conductors 13 are illustrated. It will be apparent, however, that any number of such conductors may be provided, the number depending on Ithe number of sep arate windings which are provided on the core.

The conductors 13 extend from one face of the base member 11, which will be referred to as the bottom face, to form pins l5 which are adapted to be inserted into a socket or into apertures in `a printed wiring board. The portions of the conductors 13 which extend from the opposite or upper face of the base member 11 are bent at right angles to form a supporting platform in a plane which is parallel to and spaced from the base member 11. These conductors are preferably bent radially outwardly from the axis of the base member 11 for reasons which will become apparent.

In order to facilitate the assembly of the mounting structure, the base member 11 may be placed on a pedestal or workholder 17, such as is shown in Figure 4, having apertures for receiving the pins 15. This pedestal 17 is preferably narrow to permit access to the elements for assembly. The platform which has been formed from the conductors 13 supports a Wound toroid core or ring core 19 in a manner such that the flat plane of the core lies parallel to the plane of the platform. The core 19, in the illustrated embodiment, is provided with two separate windings of insulated wire and hence has four winding leads 21 to be electrically connected. In order to provide additional insulation between the core windings and the conductors 13 which support the core, a thin disc 23 of insulating paper, or other suitable material, is rst placed over the conductors 13 forming the platform. This insulating disc 23 has a diameter which is substantially identical to the outer diameter of the core and is cemented directly to the `conductors 13. The core 19 is then placed directly over the insulating disc 23 and is cemented to the disc. The conductors 13, which form the platform, preferably extend outwardly beyond the outer periphery of the core 19 in order `to facilitate the connection of the winding leads 21 to these conductors. Each of the leads 21 is wound around one of the conductors 13 and soldered to it to provide a good electrical joint.

The above described assembly is next removed from the pedestal 17 and is placed in a casting form or mold 25 having a flat bottom wall 27 and a closed circular wall 29 extending perpendicularly from the bottom wall 27. The bottom wall is provided with apertures for receiving the pins 15 of the core assembly so that the bottom surface of the base member 11 lies contiguous to the bottom wall 27.

A housing or envelope 31 for the core assembly consists of a substantially semi-spherical member or a cylindrical member having a semi-spherical closed end. The housing 31 may be made of plastic, glass, or any other suitable material. The diameter of the housing 31 at its 3 open end is su'iciently large to surround the entire core assembly above described.

The inner diameter of the circular Wall 29 of the casting mold Z5 is substantially similar to the outer diameter of the yopen end of the housing 31 so that the housing will t relatively snugly within the wall 29.

Before placing the housing 31 within the casting mold 25 the mold is partially lled with a liquid adhesive resin or plastic 35 which sets at a low temperature. The mold is preferably filled to a level such that the base member 11 is entirely enclosed by the liquid adhesive without the adhesive contacting the core. The housing 31 is then placed within the mold Walls 29 and inserted into the mold so that the open face of the housing is contiguous to the bottom wall 27 of the mold. The housing 31 is provided with an aperture 33 adjacent its open face. This aperture is sufficiently close to the periphery of the open face of the housing 31 to permit the escape of air from within the housing as it is being inserted into the mold and so that it will be sealed by the resin within the mold. When the adhesive resin 35 sets or hardens, the Wound ring core is enclosed in an airtight structure, the housing 31 now being sealed by the adhesive resin 35.

The completed assembly is shown in Figure 7 and comprises a base which is formed by the combination of the base member 11 and the hardened resin 35, the p-ins and supporting platform formed by the conductors 13, the insulating disc 23, the wound core 19 which is carried by and connected to the conductors 13, and the housing l31.

The above described mount provides a hermetically sealed support for a wound core. One advantage of hermetic sealing, over the process of encapsulation or potting, is that it eliminates an increase in capacitance in the core windings due to the dielectric properties of the potting material. IIn the -above described mount, the dielectric is air. If it is desirable, air may be replaced with an inert gas. In the potting process, the potting material may set up magnetostrictive strains within a magnetic core. With a mount such as is described herein, this tendency is eliminated.

Referring now particularly to Figures 8, 9, and l0 of the accompanying drawings, an alternative method of assembly and an alternative structure will be described. In this alternative method of assembly, the conductors 13 are placed in a workholder 37 having parallel apertures or bores 38 extending downwardly from its upper surface. The depth of these bores 38 is equivalent to the length of the pins which are a part of the finished assembly. The workholder 37 is provided with a ilange 39 about its periphery and in the plane of its upper surface. The purpose of this ilange 39 will become apparent.

The conductors 13 are bent in the manner heretofore described to form a supporting platform for the core 19. The insulating disc 23 and the core 19 are secured to this platform in the manner previously described.

The workholder 37 is next placed on a molding form 41 having a plane supporting surface. The molding form 41 is provided with an opening 42 lfor receiving the workholder 37. The workholder is supported by the ange 39 in a manner such that the upper surface of the workholder 37 is flush with the plane surface of the form 41.

A housing 43 is substantially semi-spherical in shape and has a cylindrical extension 45 at its open end which is of slightly reduced diameter. A ring or band 47, which may be made of a plastic material, for example, is of a diameter slightly larger than the diameter of the cylindrical extension 45 so that the band 47 will fit closely over the cylindrical extension 45. Before being assembled with the housing, the band 47 is placed over the core and conductors and lies on the surface of the form 41. The ring 47 now serves as the mold form for the adhesive resin 35 and a suicient amount of resin is introduced into the form to forml a layer which encases a portion of the conductors 13. The housing 43 is again provided with an aperture 33 which permits air to escape from within the cap as it is being placed within the ring 47 and the aperture 33 is sufciently close to the periphery of the open face of the housing so that it will be sealed when the resin hardens. The hardened resin forms the closing wall for the housing and supports the conductors and core with respect to the housing.

The nal assembly is illustrated in Figure l0 and comprises the base 35, the conductors 13 forming the pins 15' and the platform, the core 19, the housing 43, and the band 47. The band 47 provides additional rigidity of the mount structure and tends to prevent separation of the housing 43 from the resin base 35 through careless handling of the core mount.

What is claimed is:

l. A mounting means for a Wound ring core comprising an open faced housing, a closing wall for said housing formed from an insulating resin, a plurality of conductors extending transversely through said Wall, said conductors on the inner side of said wall themselves dening a supporting platform parallel to said Wall, and said wound ring core being disposed on said platform and being secured to said conductors defining said platform.

2. A mounting means for a wound ring core comprising a at insulating base, a plurality of conductors extending transversely through said base, said conductors on one side of said base themselves defining a supporting platform parallel to said base, said wound ring core being disposed on said platform and being secured to said conductors defining said platform, an open faced housing disposed over said core, the open face of said housing lying in the plane of said base, and said base comprising a plastic seal encasing a portion of said conductors and closing said housing.

3. A plug-in wound core assembly comprising an insulating base member, a plurality of conductors extending transversely through said base member, said conductors on one side of said base member themselves denning a supporting plane parallel to said base member, a wound ring core disposed in said supporting plane and being secured to said conductors defining said supporting plane, the windings of said core being electrically connected to said conductors, an open faced housing disposed over said core and said base member, the open face of said housing surrounding said base member, and means comprising a plastic seal enclosing said base member and closing said housing, said conductors extending from the external side of said base member and forming pins for insertion into a socket.

4. A plug-in mount for a small wound toroid core comprising a disc-like base member, a plurality of conductors extending perpendicularly through said member and having portions projecting beyond opposite faces of said member, said portions extending perpendicularly from one face of said member providing pins for insertion in a socket, said portions extending from the other face of said member themselves defining a supporting plane substantially parallel to and spaced from said member, said toroid core being disposed in said supporting plane and secured to said portions forming said supporting plane to form a core assembly, an open faced envelope enclosing said core assembly, the open face of said envelope being disp-osed substantially in the plane of said base member, anda closure for said envelope, said `closure being composed of a hardened plastic Wall which supports said member and seals said envelope.

5. A mounting means for a small wound toroid core comprising a dise-like header having a plurality of conductors extending transversely therethrough, said conductors having their ends on one side of said header formed to provide a supporting platform substantially parallel to said header, said toroid core being disposed on said platform and being secured to said conductors forming said platform, the windings on said core being connected to said conductors forming said platform, said core and said header comprising a core assembly, an open faced envelope enclosing said assembly, said open face of said envelope being disposed in the plane of said header, a band enclosing said envelope adjacent its open face, and a plastic closure for said envelope which substantially eneases said header.

6 References Cited in the le of this patent UNITED STATES PATENTS Wermine .Tune 10, 1930 Osterman et al. Ian. 13, 1948 Hartzell June 27, 1950 Horeliek Oct. 6, 1953 Massar Jan. 11, 1955 Hampel Jan. 13, 1959 

